gearmulator

commit 4b51e97a5b4dad1b5692fea66fdea72369d28bf7
parent d086bfd5b25d9697734e7a923817f78e4fa29c99
Author: dsp56300 <dsp56300@users.noreply.github.com>
Date:   Sun, 11 Aug 2024 03:44:02 +0200

rework sync code for more accurate UC timing on slower CPUs

Diffstat:
M
source/hardwareLib/haltDSP.cpp
 | 
4
++++
M
source/hardwareLib/haltDSP.h
 | 
5
++++-
M
source/nord/n2x/n2xLib/n2xdsp.cpp
 | 
19
+++++++++++++++++++
M
source/nord/n2x/n2xLib/n2xhardware.cpp
 | 
4
++++
M
source/nord/n2x/n2xLib/n2xhardware.h
 | 
1
+

5 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/source/hardwareLib/haltDSP.cpp b/source/hardwareLib/haltDSP.cpp
@@ -65,6 +65,8 @@ namespace hwLib
 		}
 		m_cvHalted.notify_one();
 
+		m_halting = true;
+
 		// halt and wait for resume or a wakeup call
 		m_blockSem.wait();
 
@@ -88,5 +90,7 @@ namespace hwLib
 			func();
 			m_blockSem.wait();
 		}
+
+		m_halting = false;
 	}
 }
diff --git a/source/hardwareLib/haltDSP.h b/source/hardwareLib/haltDSP.h
@@ -21,7 +21,8 @@ namespace hwLib
 		void haltDSP(bool _wait = false);
 		bool resumeDSP();
 
-		bool halted() const {return m_halted > 0; }
+		// only returns true if the last halt request has been serviced
+		bool isHalting() const { return m_halting && m_irqRequestCount == m_irqServedCount; }
 
 		dsp56k::DSP& getDSP() const { return m_dsp; }
 
@@ -46,6 +47,8 @@ namespace hwLib
 		uint32_t m_wakeUpCount = 0;
 
 		std::unordered_map<uint32_t, std::function<void()>> m_wakeUps;
+
+		bool m_halting = false;
 	};
 
 	class ScopedResumeDSP
diff --git a/source/nord/n2x/n2xLib/n2xdsp.cpp b/source/nord/n2x/n2xLib/n2xdsp.cpp
@@ -150,6 +150,7 @@ namespace n2x
 	{
 		if(_needMoreData)
 		{
+			hwLib::ScopedResumeDSP rA(m_hardware.getDSPA().getHaltDSP());
 			hwLib::ScopedResumeDSP rB(m_hardware.getDSPB().getHaltDSP());
 
 			while(dsp().hasPendingInterrupts())
@@ -166,10 +167,28 @@ namespace n2x
 
 	void DSP::hdiSendIrqToDSP(const uint8_t _irq)
 	{
+		if(m_hardware.requestingHaltDSPs() && getHaltDSP().isHalting())
+		{
+			// this is a very hacky way to execute a DSP interrupt even though the DSP is halted. This case happens if the DSPs run too fast
+			// and are halted by the sync code, but the UC wants to inject an interrupt, which needs to be executed immediately.
+			// In this case, we execute the interrupt without altering the DSP state
+
+			const auto numOps = dsp().getInstructionCounter();
+			const auto numCycles = dsp().getCycles();
+
+			const auto pc = dsp().getPC();
+			dsp().getJit().exec(_irq);
+			dsp().setPC(pc);
+
+			const_cast<uint32_t&>(dsp().getInstructionCounter()) = numOps;
+			const_cast<uint32_t&>(dsp().getCycles()) = numCycles;
+		}
+		else
 		{
 			dsp().injectExternalInterrupt(_irq);
 			dsp().injectExternalInterrupt(m_irqInterruptDone);
 
+			hwLib::ScopedResumeDSP rA(m_hardware.getDSPA().getHaltDSP());
 			hwLib::ScopedResumeDSP rB(m_hardware.getDSPB().getHaltDSP());
 			m_triggerInterruptDone.wait();
 		}
diff --git a/source/nord/n2x/n2xLib/n2xhardware.cpp b/source/nord/n2x/n2xLib/n2xhardware.cpp
@@ -319,6 +319,8 @@ namespace n2x
 		if(m_dspHalted)
 			return;
 		m_dspHalted = true;
+//		LOG("Halt");
+		m_dspA.getHaltDSP().haltDSP();
 		m_dspB.getHaltDSP().haltDSP();
 	}
 
@@ -327,6 +329,8 @@ namespace n2x
 		if(!m_dspHalted)
 			return;
 		m_dspHalted = false;
+//		LOG("Resume");
+		m_dspA.getHaltDSP().resumeDSP();
 		m_dspB.getHaltDSP().resumeDSP();
 	}
 
diff --git a/source/nord/n2x/n2xLib/n2xhardware.h b/source/nord/n2x/n2xLib/n2xhardware.h
@@ -33,6 +33,7 @@ namespace n2x
 
 		void haltDSPs();
 		void resumeDSPs();
+		bool requestingHaltDSPs() const { return m_dspHalted; }
 
 		bool getButtonState(ButtonType _type) const;
 		void setButtonState(ButtonType _type, bool _pressed);